Plantetary reduction wheel hub

ABSTRACT

A planetary reduction drive, particularly for a vehicle wheel. A mounting flange adapted to be secured to the vehicle frame has a hollow spindle extending from one side, and a drive motor is mounted on the other side of the flange with its output shaft extending into the spindle. An input shaft is coupled to the motor shaft and extends outwardly from the spindle. A fixed ring gear surrounds the input shaft and is secured to the spindle adjacent its outer end. A housing has a first hub portion surrounding and rotatably mounted on the spindle and a second hub portion surrounding the fixed ring gear, the wheel being mounted on the housing. An output ring gear also surround the input shaft and is secured to the second hub portion of the housing. A planet carrier is positioned within the ring gears and supports at least two planet shafts, each of the planet shafts having a cluster of first and second planet gears thereon, the first planet gears meshing with the fixed ring gear and the second planet gears meshing with the output ring gear. The mesh of the planet gears with the ring gears comprises the sole support for the carrier. A sun gear is splined to the input shaft and meshes with one planet gear of each cluster.

United States Patent Knoblach et al. A

' 51 Aug. 29, 1972 [54] PLANTETARY REDUCTION WHEEL HUB [72] Inventors:John C. Knoblach; Ray M. Shepard,

both of Fort Wayne, Ind.

[73] Assignee: Fairfied vManufacturing.Company,

lnc., Lafayette, Ind.

[22] Filed: April 9, 1971 [21] Appl. No.: 132,707

[52] US. Cl. ..-...74/80l, 74/750 R [51] Int. Cl. ..'.....F16h l/28,F16h 3/44 [58] Field of Search ..74/801, 750 R [56] References CitedUNITED STATES PATENTS 1,632,123 6/ 1 927 Else ..74/801 1,707,877 4/1929Roberts ..74/80l 1,799,740 4/1931 Felton ..'....74/801 2,401,875 6/ 1946 Lawler ..74/80l 2,402,756 6/1946 Lawler ..74/801 X 3,319,492 5/1967Magnuson ..74/750 R 3,502,166 3/1970 Christenson et al.....74/801 XPrimary Examiner--Arthur T. McKeon Attorney-Thomas P. Jenkins, Jack W.Hanley, Jerry E. Hyland and Ralph W. Burnett [57] ABSTRACT A planetaryreduction drive, particularly for a vehicle wheel. A mounting flangeadapted to be secured to the vehicle frame has a hollow spindleextendingfrom one side, and a drive motor is mounted on the other side of theflange with its output shaft extending into the spindle. An input shaftis coupled to the motor shaft and extends outwardly from the spindle. Afixed ring gear surrounds the input shaft and is secured to the spindleadjacent its outer end. A housing has a first hub portion surroundingand rotatably mounted on the spindle and a second hub portionsurrounding the fixed ring gear, the wheel being mounted on the housing.An output ring gear also surround the input shaft and is secured to thesecond hub portion of the housing. A planet carrier is positioned withinthe ring gears and supports at least two planet shafts, each of theplanet shafts having a cluster of first and second planet gears thereon,the first planet gears meshing with the fixed ring gear and the secondplanet gears meshing with the output ring gear. The mesh of the planetgears with the ring gears comprises the sole support for the carrier. Asun gear is 'splined to the input shaft and meshes with one planet gearof each cluster.

20 Claims, 14 Drawing Figures Patented Aug. 29, 1972 9 Sheets-Sheet l:CA SOP r RLE mm Q m Nc p/ w J ATTQIQNEYL.

Patented Aug. 29, 1972' 3,686,978

- 9 Sheets-Sheet 2 FIGM- INVENTORS. JOHN Q- KNOBLOcH,

PAY M SHEPARD,

A1- ToQNzYs.

- 9 Sheets-Sheet 5 INVENTOFPSI JOHN C. KNoaLocr-q,

RAY M.SHEPAIPD,

ATTORNEYS- Patented Aug. 29, 1972 3,686,978

- i 9 Sheets-Sheet 4 Patented Aug. 29, 1972 9 Sheets-Sheet 5 ,NVENTORS.

C- l -osLocH RAY M. SHEP BY A JOHN

A RD,

YT RNEYS.

Patented Aug. 29, 1972 3,686,918

9 Sheets-Sheet 7 INVENTORS. JOHN C. KNOBLOCH,

QAY M. SHEPARD,

ATTORNEYS PLANTETARY REDUCTION WHEEL HUB BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates generally to planetaryreduction drives, and more particularly to a planetary reduction drivefor a vehicle wheel.

2. Description of the Prior Art Certain types of wheeled vehicles, suchas earth movers, mine shuttle cars, lumber transfer vehicles andagricultural implements employ so called motorized wheels," i.e., aselfcontained power drive for each wheel comprising an electric orhydraulic driving motor and a gear reduction unit generally accommodatedwithin the hub of the wheel. In certain prior powered wheel hubs, themotor and gear train are integrated in a single assembly thusnecessitating removal of the entire wheel in order to repair or replacethe motor and providing a complex mechanism which is difficult toassemble and disassemble. Other prior powered wheel hubs have required aspecially designed driving motor and cannot readily be adapted for usewith a different motor. Prior powered wheel hubs have generally employeda planetary reduction gear train however, change of the gear ratio inthe field has either been impossible or has necessitated substantialdisassembly and reassembly of the gear train.

It is therefore desirable to provide a powered wheel hub employing astandard drive motor which can readily be replaced without removal ofthe hub and wheel, in which the gear ratio may readily be changed in thefield, and which is generally characterized by its simplicity and easeof assembly and disassembly.

SUMMARY OF THE INVENTION A planetary reduction drive which comprises amounting flange having a hollow spindle extending outwardly from oneside thereof, means for securing the flange to a support member such asa vehicle frame element, and means for mounting a drive motor on theother side of the flange with its output shaft extending into thespindle. An input shaft coaxial with the motor shaft has a first portionextending into the spindle and a second portion extending outwardly fromthe outer end of the spindle, and means are provided for coupling thefirst portion of the input shaft to the motor shaft. A fixed ring gearcoaxially surrounds the second portion of the input shaft and is securedto the spindle adjacent its outer end. A housing is provided having afirst hub portion surrounding and rotatably mounted on the spindle, asecond hub portion surrounding the fixed ring gear, and means formounting a rotatable driven element, such as a wheel. An output ringgear coaxially surrounds the second portion of the input shaft outwardlyfrom the fixed ring gear and is secured to the second hub portion of thehousing. A planet carrier is disposed within the ring gears and supportsat least two planet shafts, each of the planet shafts having a clusterof first and second planet gears thereon connected to rotate in unison,with the first planet gears meshing with the fixed ring gear and thesecond planet gears meshing with the output ring gear, the mesh of theplanet gears with the ring gears providing the sole support for thecarrier. At least one sun gear is provided on the second portion of theinput shaft and meshing with one planet gear of each cluster, and meansare provided for connecting the sun gear to the second portion of theinput shaft for rotation therewith.

It is accordingly an object of the invention to provide an improvedplanetary reduction drive.

Another object of the invention is to provide an improved planetaryreduction wheel hub.

A further object of the invention is to provide an improved planetaryreduction drive wherein the drive motor may readily be replaced and thegear reduction ratio changed without substantial disassembly of thedrive.

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will be best understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 composed of FIGS. 1A and 1B isan exploded, partially broken away, perspective view showing a poweredwheel hub incorporating one embodiment of the invention;

FIG. 2 is a side cross-sectional view showing the embodiment of FIG. 1;

FIG. 3 is a cross-sectional view taken generally along the line 3-3 ofFIG. 2;

FIG. 4 is a cross-sectional view taken generally along the line 4-4 ofFIG. 2;

FIG. 5 is a cross-sectional view taken generally along the line 5-5 ofFIG. 2;

FIG. 6 is a fragmentary cross-sectional view taken generally along theline 6-6 of FIG. 2;

FIG. 7 is a fragmentary side view showing the drive of the previousfigures with the sun gear meshing with the second planet gears;

FIG. 8 is a fragmentary side cross-sectional view showing anotherembodiment of the invention which provides shifting between two gearratios without any disassembly of the unit;

FIG. 9 is a fragmentary side cross-sectional view showing anotherembodiment of the invention incorporating a remotely controlled gearshifting mechanism;

FIG. 10 is a fragmentary side cross-sectional view showing yet anotherembodiment of the invention incorporating another remotely controlledgear shifting mechanism; 7

FIG. 11 is a fragmentary side cross-sectional view showing applicationof a braking system to the planetary reduction drive of the invention;

FIG. 12 is a fragmentary side cross-sectional view showing adaptation ofthe planetary reduction drive of the invention to drive a sprocket; and

FIG. 13 is a fragmentary cross-sectional view showing a furtherembodiment of the invention incorporating a disconnect.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1through 7 of the drawings, the planetary reduction drive hub of theinvention, generally indicated at 20, comprises six readily assembledand disassembled major components, i.e., spindle and hub assembly 22,24, fixed ring gear 26, planet carrier and gear cluster assembly 28,output ring gear 30, splined shaft and sun gear assembly 32, and cover34. Mounting flange 36 of spindle 22 is removably secured to frameelement .38 of the vehicle by threaded fasteners 40. Drive motor 42,commonly a hydraulic motor, is removably secured to flange 36 bythreaded fasteners 44 and has its splined output shaft 46 extending intohollow spindle 48 and removably coupled to splined input shaft 50 bysplined coupling 78. Wheel 54 having tire 56 thereon is removablysecured to flange 58 of hub 24 by threaded fasteners 60.

Referring now more particularly to FIGS. 2 through 7, spindle assembly22 comprises mounting flange 36 having hollow spindle 48 extendingoutwardly from one side thereof. Flange 36 is secured to vehicle frameelement 38 by threaded fasteners 40, opening 62 in element 38 receivingboss 64 of flange 36. Flange 66 of motor 42 is secured to boss 64 bythreaded fasteners 44, motor 42 having boss 68 received in recess 70 inflange 36. Splined output shaft 46 of motor 42 extends into hollowspindle 48.

Splined input shaft 50 has a first or inner portion 72 extending intohollow spindle 48 and a second or outer portion 74 extending outwardlyfrom outer end 76 thereof. Motor shaft 46 and inner input shaft portion72 are removably connected by splined coupling 78, snap ring 80 properlypositioning coupling 78.

Fixed ring gear 26 comprises a cup-shaped member having internal ringgear teeth 82 formed on its side wall 84. Fixed ring gear 26 isremovably mounted on hollow spindle 48 adjacent outer end 76 by asplined connection comprising external splines 86 on hollow spindle 48and internal splines 88 in end wall 90.

Hub assembly 24 comprises first orv inner hub portion 92 and second orouter hub portion 94. Inner hub portion 92 is rotatably mounted onhollow spindle 48 between end wall 90 of fixed ring gear 26 and flange36 by roller bearings 96. Seal 98 prevents passage of lubricant out ofinner hub portion 92. Outer hub portion 94 concentrically surroundsfixed ring gear 26. Spacer 100 and snap ring 102 retain bearings 96-andhub assembly 24 in assembled relationship on hollow spindle 48.

- hub portion 94 by threaded fasteners 1 12.

Planet carrier 114 is coaxially positioned within ring gears 26, 30 androtatably supports three planet shafts 116. Each of the planet shafts116 has a gear cluster 118 thereon comprising first and secondintegrally formed planet gears 120, 122 which rotate in unison.

Gear clusters 118 are rotatably supported on planet shafts 116 by rollerbearings 124 having spacer 126 therebetween.

Planet shafts 116 extend between and are supported by end walls 128, 130of carrier 114, end walls 128, 130 being integrally connected by webs132 disposed between gear clusters 118, as best seen in FIGS. 3 through6. Planet shafts 116 are secured against rotation and axial movement byroll pins 134. Thrust washers 136 are positioned between the oppositeends of gear clusters 118 and C-shaped bosses 138 formed on end walls128, of carrier 114, as best seen in FIGS. 2, 3 and 6. Thrust washers136 have inwardly formed tangs 140 which extend between ends 142 ofbosses 138 (FIGS. 3 and 6) thereby preventing rotation of thrust washers136 with rotation of gear clusters 1 18 and reducing wear of bosses 138.Thrust washers 144 are positioned between carrier end wall 128 and cover34 and carrier end wall 130 and end wall 90 of fixed ring gear 26,respectively. First planet gears 120 mesh with teeth 82 of fixedringgear 26 and second planet gears 122 mesh with teeth 104 of outputring gear 30. As illustrated in FIGS. 2 through 6, sun gear has asplined connection with outer portion 74 of splined input shaft 50 andmeshes with first planet gears 120, sun gear 150 being retained inposition by snap rings 152. It will be seen that the mesh of planetgears 120, 122 with ring gears 26, 30 provides the sole support forcarrier 1 14.

Flange 58 is formed on hub assembly 24 generally intermediate inner hubportion 92 and outer hub portion 94. Wheel 54 is removably mounted onflange 58 by threaded fasteners 60 having conventional lugs 154 thereon.The outer surface of inner hub portion 92 preferably has a plurality ofangular spaced slots 156 formed therein. Pin 158 may be inserted in aslot 156, as shown by the dashed lines in FIG. 2, thereby to pro vide aparking brake. Thrust washer 160 is positioned between outer end 162 ofsplined shaft 50 and boss 164 on cover 34, thrust washer 160 havingflange 166 seated in opening 168 in boss 164. Thrust washer 160 also hastang 170 extending into slot 172 in boss 164 for preventing rotation ofthrust washer 160 with rotation of splined input shaft 50 and thusinhibiting wear of boss 164.

Referring now additionally to FIG. 7 it will be seen that sun gear 150of the previous figures has been removed from outer portion 74 ofsplined shaft 50 and a different sun gear 174 positioned thereon in meshwith second planet gears 122, sun gear 174. being retained on splinedinput shaft portion 74 by snap rings 176. In order to substitute sungear 174 for sun gear 150 and thereby change the gear ratio, it ismerely necessary to remove threaded fasteners l12 thus permittingremoval of cover 34 and output ring gear 30, then to remove planetcarrier and gear. cluster assembly 28 bodily, and finally to removesplined input shaft and sun gear assembly 32 bodily. Snap rings 152 maythen be removed thus permitting removal of sun gear 150 from portion 74of splined shaft 50. Sun gear 174 may then be positioned on portion 74of splined shaft 50 and retained by snap rings 176, and remainingcomponents reassembled in reverse sequence.

It will further be seen that a wide range of gear ratios may be providedwithout removing hub assembly 24 and wheel 54 from spindle assembly 22.Thus, an output ring gear 30 having a different number of internal teeth104 may readily be substituted by merely removing threaded fasteners l12 and cover 34. Further, upon removal of cover 34, .output ring gear 30and planet carrier and gear cluster assembly 28, fixed ring gear 26 mayreadily be removed from hollow spindle 48 and another fixed ring gear'26having a different number of internal teeth 82 substituted therefor.Finally, by driving roll pins 134 completely into holes 135 in planetshafts 1 16, the planet shafts may be removed from carrier 114, gearclusters 118 removed, and other gear clusters having different numbersof teeth on planet gears 120, 122 substituted therefor. After drivingroll pins 134 completely into holes 135 and removing planet shafts 116,roll pins 134 may then be driven out of holes 135 and reassembled asshown in FIG. 2. The following tabulation shows a number of differentgear ratios provided with five different output ring gears 30, sixdifferent sun gears 150, 174 and five different gear clusters 118employing five different planet gears 122, each of the five differentgear clusters 118 employing the same number of teeth in planet gears120. Only one fixed ring gear 26 is employed:

GEAR REDUCTION RATIOS gears 120. Sun gear 174, being disengaged, merelyfree-wheels in response to rotation of gear clusters 118. Actuatingmember 186 and input shaft 50' are maintained in this position byengagement of detent notch 206 with detent ball 208.

Actuation of actuating member 186 rearwardly to the position as shown indashed lines at 200a will move outer end 162 of input shaft 50'rearwardly into recess 192 to the position shown in dashed lines at1620, actuating member 186 and input shaft 50' being retained in thisposition by engagement of detent notch 204 with detent ball 208. In thisposition, splined section 178 on outer portion 74' of input shaft 50 ispositioned between splined sections 180, 182 of sun gears 150', 174, asshown in dashed lines at 1780, thus providing a neutral position.Further rearward movement of acixed rin ear 26 79 79 79 79 79 79 79 7979 79 lanet ger 120 25 25 25 25 25 25 25 25 25 Planet gear 122 33 32 3133 32 31 30 28 28 Output ring gear 30. 87 86 85 84 87 86 85 84 82 82 Sungear 150.. 29 29 29 29 29 Sun gear 174-. 21 22 23 24 26 It will bereadily apparent that by providing a number of different ring gears 26having different numbers of teeth and an additional number of gearclusters 118 having planet gears 120 with different numbers of teeth, amuch wider range of gear reduction ratios may be provided. FIGS. 2through 7 of the drawings are roughly to onehalf scale. A planetaryreduction drive hub as shown in FIGS. 2 through 7 with gearing providinga gear reduction ratio of 34.5/1, as shown in the tabulation above, andwith a hydraulic motor 42 having two cubic inch per revolutiondisplacement operated at 4,500 psi, provided approximately 50,000 poundinches of output torque.

Referring now to FIG. 8 in which like elements are indicated by likereference numerals and similar elements by primed reference numerals, anelongated hollow spindle 48' is provided and inner portion 72' of inputshaft 50' and splined coupling 78' are also elongated. Inner portion 72'of input shaft 50' is splined and outer portion 74' has a relativelyshort splined section 178 thereon. Two sun gears 150 and 174' areprovided at all times respectively in mesh with planet gears 120, 122 ofgear clusters 118. Sun gears 150', 174' have internally splined sections180, 182, respectively. Sun gear 150 has spacing portions 151 on itsopposite sides. Spacer 153 locates sun gear 174.

Annular groove 184 is formed in outer portion 74' of input shaft 50'adjacent outer end 162 and shift actuating member 186 has end portion188 received in groove 184. Cover 34' has an outwardly projecting hubportion 190 with a recess 192 formed therein coaxially with input shaft50'. Actuating member 186 extends through and is slideably received inslot 194 in recess 192 and opening 196 in end wall 198 of hub 190. Actuating knob 200 is attached to the end of actuating member 186.Actuating member 186 has three spaced apart detent notches 202, 204 and206 formed therein, and a detent ball 208 biased inwardly by spring 210is seated in opening 212 in hub 190.

It will now be seen that with actuating member 186 positioned forwardlyas shown in solid lines in FIG. 8, input shaft 50' will be positionedforwardly with its splined section 178 drivingly engaging splinedsection 180 on sun gear 150. Sun gear 150' thus drives planet tuatingmember 186 to the position shown in dashed lines at 20% thus movingouter end 162 of input shaft 50' rearwardly to the position shown indashed lines at 162b will move splined section 178 of outer portion 74'of input shaft 50 into engagement with splined section 182 of sun gear174', engagement of detent notch 202 with detent ball 208 retainingactuating member 186 and splined shaft 50' in this position. In thisposition, sun gear 174 is driven thus driving planet gears 122. Sun gearbeing disengaged from outer portion 74' of input shaft 50' isfree-wheeling. It will be seen that the elongated splined coupling 78'permits this axial shifting of inner portion 72' of input shaft 50'.

Referring now to FIG. 9 in which like elements are again indicated bylike reference numerals and similar elements by double primed referencenumerals, flange 36" of spindle assembly 22 has an enlarged boss 214formed thereon from which hollow spindle 48'' ex tends. Sleeve 216surrounds outer portion 74 of splined input shaft 50 and has a splinedconnection therewith, as at 218. Sun gears 150" and 174" are rotatablymounted on sleeve 216. Flanges 220, 222 are respectively formed on theopposite ends of sleeve 216 and respectively have clutch teeth 224, 226formed thereon. Cooperating clutch teeth 228, 230 are formed on thesides of sun gears 150", 174". Spacing portions 151" and spacer 186"locate sun gears 150", 174".

Sleeve 216 is shifted axially from a position in which its clutch teeth224 drivingly engage clutch teeth 228 on sun gear 150", as shown insolid lines in FIG. 9, to a position in which its clutch teeth 226drivingly engage clutch teeth 230 on sun gear 174", as shown in dashedlines at 220a, by push rod 232 engaging flange 220 on sleeve 216 andextending axially through opening 234 in spindle 48" into cavity 236 inboss 214. Projection 238 having cam surface 240 thereon is formed oninner end 242 of push rod 232 in cavity 236. Spring 244 normally biasessleeve 216 to position 220a in which teeth 226 drivingly engage teeth230 on sun gear 174".

Remotely controlled actuator 246, which may be a fluid power cylinder ora solenoid, has extensible element 248 engaging cam surface 240. Thus,remote actuation of actuator 246 to extend element 248 will move pushrod 232 toward the right as viewed in FIG. 9

so as to cause teeth 224 drivingly to engage teeth 228 on sun gear 150".Actuator 246 is retained in opening 250 communicating with cavity 236 byspacer 252 and threaded plug 254.

A parking brake may also be employed in conjunction with the shiftingmechanism shown in FIG. 9. Member 256 having teeth 258 thereon isnormally accommodated in recess 260 in end 76 of hollow spindle 48".Push rod 262 is connected to member 256 and extends axially throughopening 264 in spindle 48" into cavity 236. Projection 266 on end 268 ofpush rod 262 has cam surface 270 thereon. Spring 272 normally biasespush rod-262 so as to position member 256 and teeth 258 in recess 260.Remotely controlled fluid power or solenoid actuator 274 has extensibleelement 276 cooperatively engaging cam surface 270. Flange 220 of sleeve216 has braking teeth 278 on its outer surface. Remote actuation ofactuator 274 to extend element 276 will move push rod 262 toward theright as viewed in FIG. 9 thus moving teeth 258 on member 256 intoengagement with teeth 278 on sleeve 216, further moving sleeve 216toward the right against spring 244 I thereby causing teeth 224 toengage teeth 228 on sun gear 150". Thus, sun gear 150 is locked againstrotation thereby locking the entire gear train. Actuator 274 is retainedin opening 275 communicating with cavity 236 by spacer 277 and threadedplug 279.

Referring now to FIG. 10 in which like elements are again indicated bylike reference numerals and similar elements by triple primed referencenumerals, sleeve 280 surrounds outer portion 74 of splined shaft 50,being retained thereon by snap rings 282. Sun gears 150", 174" arerotatably mounted on sleeve 280. Sun gears 150", 174" respectively havedriven clutch discs 284, 286 secured thereto, as by welding, andrespectively spaced from their outer faces. Stationary clutch discs'288,290 are splined on outer portion 74 of splined input shaft 50,respectively abutting snap rings 282, and 292. Pressure clutch discs294, 296 respectively have splined connections with outer portion 74 ofsplined input shaft 50, driven discs 284, 286 being respectivelypositioned between stationary discs 288, 290 and pressure discs 294,296. Stationary discs 288, 290 and pressure discs 294, 296 arerespectively normally biased apart by springs 298, 300.

Pressure disc 294 is moved toward the right as viewed in FIG. 10 therebyto engage driven disc 284 and to move it and sun gear 150" slightlytoward the right so that disc 284 engages stationary disc 288, by pushrod 232 which may be remotely actuated by actuator 246 (FIG. 9). Thus,actuation of push rod 232 clamps driven disc 284 between stationary disc288 and pressure disc 294, both of which are splined on input shaft 50,thus drivingly connecting sun gear 150" to the input shaft.

Pressure disc 296 is moved toward the left as viewed in FIG. 10 therebyto engage driven disc 286 and to move it and sun gear 174" slightlytoward the left so that driven disc 286 engages stationary disc 290, by

I push rod 302 extended by actuator 304 seated in recess 306 in cover 34and retained therein by threaded plug 308. Actuator 304 is shown as afluid power cylinder having its pressure line 310 coupled to line 312 byrotatable coupling 314. Actuation of actuator 304 to extend push rod 302will clamp driven disc 286 between stationary disc 290 and pressure disc296, both of which are splined to outer portions 74 of splined inputshaft 50, thus drivingly connecting sun 8 gear 174" to the input shaft.It will further be seen that simultaneous actuation of actuator 246(FIG. 9) and actuator 304 will result in connecting both sun gears and174" to outer portion 74 of splined input shaft 50 thereby locking thegear train to provide a parking brake action.

Referring now to FIG. 11 in which like elements are again indicated bylike reference numerals, annular brake disc 316 may be secured to theside of flange 58 remote from wheel 54 by threaded fasteners 318, disc316 having suitable brake face material 320 thereon adjacent its outerperiphery 322. Caliper mechanism 324 is secured to frame element 38 bythreaded fasteners 326 and has caliper arms 328, 330 straddling theperipheral region of disc 316. Braking action is provided by actuationof mechanism 324 to move caliper arms 328, 330 into braking engagementwith braking surfaces 320 of brake disc 316.

Referring now to FIG. 12 in which like elements are indicated by likereference numerals, the planetary reduction drive hub of the inventionmay be employed for driving rotatable driven elements other than wheels,such as the drum of a transit mix concrete mixer. Here, drive sprocket332 is secured to flange 58 of hub assembly 24 by threaded fasteners334, sprocket 332 in turn driving a chain (not shown) which drivesanother rotatable driven element.

Referring now to FIG. 13 in which like elements are indicated by likereference numerals and similar elements by quadruple primed referencenumerals,

disconnect member 336 is provided which may be a separate elementabutting end 162 of input shaft 50 or which may be formed as an integralextension of input shaft 50"". Disconnect member 336 extends throughopening 338 in hub portion 340 of .cover 34"", seal 342 preventingpassage of lubricant along disconnect member 336. Disconnect cap 344 hashollow hub portion 346 and annular flange portion 348 removably securedto hub 340 by threaded fasteners 350. In the driving position of thedrive, end 3520f disconnect member 336 extends into hub portion 346 ofdisconnect cap 344, as shown in FIG. 13. As will hereinafter be morefully described, in the disconnect or free-wheeling position of thedrive, disconnect cap 344 is reversed so that hub portion 346 extendsinto cavity 354 in hub 340 thereby engaging end 352 of disconnect member336 and moving it and input shaft 50"" to the left, as viewed in FIG.13, thereby positioning inner input shaft portion 72 as shown in dashedlines at 356. In this embodiment, output ring gear 10 is integrallyformed on cover 34"".

Outer portion 74"" of input shaft 50"" has two splined sections 358, 360thereon with unsplined portion 362 therebetween. In the driving positionof input shaft 50"" as shown in FIG. 13, splined section 358 engagesinternal splines 364 on sun gear 150"" when that sun gear is employed,and splined section 360 engages internal splines 366 on sun gear 174""when that sun gear is employed, it being understood that while both sungears 150"" and 174" are shown in FIG. 13, only one sun gear is utilizedin the drive at any given time. Spacers 368, 370 locate sun gear 150""when that sun gear is employed, and spacers 372, 374 locate sun gear174" when that sun gear is employed.

A pair of spaced-apart snap rings 376, 378 are seated in grooves oninput shaft 50"" between inner portion 72 and splined portion 58.Retaining rings 380, 382 are biased-apart by coil spring 384 and in thedrive position of input shaft 50", respectively engage snap rings 376,378. Coil spring 384 and retainer rings 380, 382 are accommodated inrecesses 386, 388 respectively formed in spindle 48 and in spacer 368 or372, recesses 386, 388 respectively having shoulders 390, 392.

It will now be seen that when disconnect cap 344 is reversed as abovedescribed with hub portion 346 engaging end 352 of disconnect member336, snap ring 378 engages retainer ring 382 thus compressing spring 384against retainer ring 380 which engages shoulder .390 as inner end 72 ofinput shaft 50" moves to the left to the dashed line position 356. Itwill further be seen that upon such movement of shaft 50" to thedisconnect position, splined section 358 will move to the left out ofengagement with splines 364 of sun gear 150"" if that sun gear isemployed, or splined section 360 will move to the left out of engagementwith splines 366 of sun gear 174"" if that sun gear is employed, thuspermitting free-wheeling of the planetary reduction drive.

Assuming that disconnect cap 344 has been reversed thereby shiftinginput shaft 50' to its disconnect position, as above-described, uponremoval of disconnect cap 344 by removing threaded fasteners 350, spring384 acting upon retainer ring 382 and snap ring 376 will bias inputshaft 50"" toward the right to its drive position, as shown in FIG. 13.It will be noted that in the drive position, spring 384 acts betweensnap rings 376, 378 and thus applies no force to the input shaft 50! I II It will now be seen that drive motor 42 may readily be removed forrepair and replacement by merely removing threaded fasteners 44 withoutthe necessity for moving wheel 54 and drive hub 20. It will further beseen that gear ratios may readily be changed again without the necessityfor removing the entire wheel and drive hub assembly and in particular,without extensive disassembly and reassembly of the gear train.

While there have been described above the principles of this inventionin connection with specific apparatus, it is to be clearly understoodthat this description is made only by way of example and not as alimitation to the scope of theinvention.

What is claimed is:

l. A planetary reduction drive comprising: a mounting flange having ahollow spindle extending outwardly from one side thereof, said spindlehaving an outer end, means for securing said flange to a support member,and means for mounting a drive motor on the other side of said flangewith its output shaft extending into said spindle; an input shaftcoaxial with said motor shaft having a first portion extending into saidspindle and a second portion extending outwardly from said outer endthereof; means for coupling said first portion of said input shaft tosaid motor shaft; a fixed ring gear coaxial with and surrounding saidsecond portion of said input shaft, and means for securing said fixedring gear to said spindle adjacent said outer end thereof; a housinghaving a first hub portion surrounding and rotatably mounted on saidspindle, a second hub portion surrounding said fixed ring gear, andmeans for mounting a rotatable driven element on said housing; an outputring gear coaxial with and surrounding said second portion of said inputshaft, secured to said second hub portion of said housing, and spacedoutwardly from said fixed ring gear; a planet carrier within said ringgear and supporting at least two planet shafts in spaced, parallelrelationship with said second portion of said input shaft, each of saidplanet shafts having a cluster of first and second planet gears thereonconnected to rotate in unison, said first planet gears meshing with saidfixed ring gear and said second planet gears meshing with said outputring gear; at least one sun gear on said second portion of said inputshaft and meshing with one planet gear of each cluster; and means forconnecting said sun gear to said second portion of said input shaft forrotation therewith.

2. The drive of claim 1 wherein the mesh of said planet gears with saidring gears comprise the sole support for said carrier.

3. The drive of claim 1 wherein said coupling means removably couplessaid input shaft to said motor shaft and said securing means removablysecures said fixed ring gear to said spindle, said output ring gearbeing removably secured to said second hub portion of said housing.

4. The drive of claim 3 wherein said fixed ring gear is carried on theside wall of a cup-shaped member, said cup-shaped member having an endwall, said securing means comprising a splined connection between saidend wall and said spindle.

5. The drive of claim 3 wherein said second hub portion has an outerend, and further comprising means for removably securing said outputring gear to said outer end of said second hub portion.

6. The drive of claim 5 further comprising a cover member having a rimportion abutting said output ring gear, said last-named securing meanscomprising threaded fasteners securing said cover member and output ringgear to said outer end of said second hub portion.

7. The drive of claim 1 wherein said connecting means comprises asplined connection between said second portion of said input shaft andsaid sun gear.

8. The drive of claim 7 wherein said splined connection comprisesexternal splines extending substantially the length of said secondportion of said input shaft, and mating internal splines on said sungear removably connecting the same to said external splines whereby aselected sun gear may be selectively meshed with the first or secondplanet gears of said clusters.

9. The drive of claim 1 wherein said motor shaft and first portion ofsaid input shaft respectively have external splines thereon, saidcoupling means comprising an internally splined sleeve removablycoupling said shafts, said fixed ring gear being carried on the sidewall of a cup-shaped member, said cup-shaped member having an end wall,said securing means comprising a splined connection removably connectingsaid end wall to said spindle, said second hub portion having an outerend, said output ring gear being carried by an annular member abuttingsaid outer end of said second hub portion, and further comprising acover member having a rim portion abutting said annular member, threadedfasteners removably securing said cover member and annular member tosaid outer end of said second hub portion, and bearing means rotatablymounting said first hub portion on said spindle intermediate said endwall of said cup-shaped member and said plate member.

portion of said cover member define a continuous cylindrical outersurface.

11. The drive of claim 1 wherein said driven element mounting meanscomprises an annular flange intermediate said first and second hubportions of said housmg.

12. The drive of claim 1 wherein there are two of said sun gearsrespectively in mesh with said first and second planet gears, saidconnecting means comprising means for selectively connecting one or theother of said sun gears to said second portion of said input shaftthereby providing two difi'erent speed reduction ratios for said drive.

13. The drive of claim 12 wherein each of said sun gears has internalsplines thereon, said second portion of said input shaft having anexternally splined section,

said selective connecting means comprising means for axially shiftingsaid input shaft between a first position with said splined sectionengaging the internal splines of one of said pinions and a secondposition with said splined section engaging the internal splines of theother of said pinions.

14. The drive of claim 13 wherein said shifting means has anintermediate position with said splined section of said input shaftspaced between said internal splines of said sun gears.

15. The drive of claim 12 wherein said selective connecting meanscomprises an axially movable sleeve surrounding and having a splinedconnection with said 17. The drive of claim 16 wherein said sun gearsare rotatably mounted on said second portion of said input shaft, eachof said clutch means comprising a driven second portion of said inputshaft and having opposite ends, said sun gears being rotatably mountedon said sleeve between said ends thereof, said sun gears respectivelyhaving clutch teeth on the sides thereof facing said ends of saidsleeve, said sleeve having clutch teeth respectively formed on saidopposite ends thereof, and means for selectively axially shifting saidsleeve between a first position with the clutch teeth at one end thereofengaging the clutch teeth on one sun gear and with the clutch teeth atthe other end disengaged from the clutch teeth on the other sun gear,and a second position with the clutch teeth at the other end of saidsleeve engaging the clutch teeth on the other sun gear and the clutchteeth at said one end disengaged from the clutch teeth on said one sungear.

16. The drive of claim 12 wherein said selective connecting meanscomprises first and second clutch means for respectively drivinglyconnecting said sun gears to said second portion of said input shaft.

clutch disc secured to the respective sun gear and spaced therefrom, astationary clutch disc secured to said second portion of said inputshaft between said driven disc and the respective sun gear, a pressureclutch disc having a splined connection with said second portion of saidinput shaft, said driven disc being disposed from said stationary discand pressure disc, spring means for normally biasing said pressure andstationary discs away from engagement with said driven disc, and meansfor selectively moving said pressure disctoward said driven disc therebydrivingly to clamp said driven disc between said stationary and i .ii1i% e of claim 17 further comprising first actuator means mounted in saidspindle for actuating the pressure disc of one of said clutch means, acover member secured to said second hub portion of said housing, andsecond actuator means mounted in said cover for actuating the pressuredisc of the other of said clutch means.

19. The drive of claim 1 wherein said connecting means comprises asplined section on said input shaft and mating splines on said sun gear,said input shaft being axially movable between a drive position withsaid splined section engaging said sun gear splines, and a disconnectedposition with said splined section disengaged from said sun gearsplines.

20. The drive of claim 19 further comprising spring means for normallybiasing said input shaft to said drive position thereof, a cover membersecured to said second hub portion, said cover member having a hubportion coaxial with said input shaft and having a coaxial openingtherethrough, a disconnect member in said opening and axially movabletherein with said input shaft between said positions thereof, and adisconnect cap removably secured to said cover member and covering saidopening therein, said cap having a projection thereon, said cap beingadapted to be secured to said cover member in a first position with saidprojection disengaged from said disconnect member, said spring meansbiasing said input shaft and disconnect member to said drive position insaid first cap position, said cap being adapted to be secured to saidcover member in a second position with said projection engaging saiddisconnect member and moving the same and said shaft to saiddisconnected position in said second cap position.

1. A planetary reduction drive comprising: a mounting flange having ahollow spindle extending outwardly from one side thereof, said spindlehaving an outer end, means for securing said flange to a support member,and means for mounting a drive motor on the other side of said flangewith its output shaft extending into said spindle; an input shaftcoaxial with said motor shaft having a first portion extending into saidspindle and a second portion extending outwardly from said outer endthereof; means for coupling said first portion of said input shaft tosaid motor shaft; a fixed ring gear coaxial with and surrounding saidsecond portion of said input shaft, and means for securing said fixedring gear to said spindle adjacent said outer end thereof; a housinghaving a first hub portion surrounding and rotatably mounted on saidspindle, a second hub portion surrounding said fixed ring gear, andmeans for mounting a rotatable driven element on said housing; an outputring gear coaxial with and suRrounding said second portion of said inputshaft, secured to said second hub portion of said housing, and spacedoutwardly from said fixed ring gear; a planet carrier within said ringgear and supporting at least two planet shafts in spaced, parallelrelationship with said second portion of said input shaft, each of saidplanet shafts having a cluster of first and second planet gears thereonconnected to rotate in unison, said first planet gears meshing with saidfixed ring gear and said second planet gears meshing with said outputring gear; at least one sun gear on said second portion of said inputshaft and meshing with one planet gear of each cluster; and means forconnecting said sun gear to said second portion of said input shaft forrotation therewith.
 2. The drive of claim 1 wherein the mesh of saidplanet gears with said ring gears comprise the sole support for saidcarrier.
 3. The drive of claim 1 wherein said coupling means removablycouples said input shaft to said motor shaft and said securing meansremovably secures said fixed ring gear to said spindle, said output ringgear being removably secured to said second hub portion of said housing.4. The drive of claim 3 wherein said fixed ring gear is carried on theside wall of a cup-shaped member, said cup-shaped member having an endwall, said securing means comprising a splined connection between saidend wall and said spindle.
 5. The drive of claim 3 wherein said secondhub portion has an outer end, and further comprising means for removablysecuring said output ring gear to said outer end of said second hubportion.
 6. The drive of claim 5 further comprising a cover memberhaving a rim portion abutting said output ring gear, said last-namedsecuring means comprising threaded fasteners securing said cover memberand output ring gear to said outer end of said second hub portion. 7.The drive of claim 1 wherein said connecting means comprises a splinedconnection between said second portion of said input shaft and said sungear.
 8. The drive of claim 7 wherein said splined connection comprisesexternal splines extending substantially the length of said secondportion of said input shaft, and mating internal splines on said sungear removably connecting the same to said external splines whereby aselected sun gear may be selectively meshed with the first or secondplanet gears of said clusters.
 9. The drive of claim 1 wherein saidmotor shaft and first portion of said input shaft respectively haveexternal splines thereon, said coupling means comprising an internallysplined sleeve removably coupling said shafts, said fixed ring gearbeing carried on the side wall of a cup-shaped member, said cup-shapedmember having an end wall, said securing means comprising a splinedconnection removably connecting said end wall to said spindle, saidsecond hub portion having an outer end, said output ring gear beingcarried by an annular member abutting said outer end of said second hubportion, and further comprising a cover member having a rim portionabutting said annular member, threaded fasteners removably securing saidcover member and annular member to said outer end of said second hubportion, and bearing means rotatably mounting said first hub portion onsaid spindle intermediate said end wall of said cup-shaped member andsaid plate member.
 10. The drive of claim 9 wherein said second portionof said hub member, said annular member, and said rim portion of saidcover member define a continuous cylindrical outer surface.
 11. Thedrive of claim 1 wherein said driven element mounting means comprises anannular flange intermediate said first and second hub portions of saidhousing.
 12. The drive of claim 1 wherein there are two of said sungears respectively in mesh with said first and second planet gears, saidconnecting means comprising means for selectively connecting one or theother of said sun gears to said second portion of said input shaftthereby providing two different speed reduction ratios for said drive.13. The drive of claim 12 wherein each of said sun gears has internalsplines thereon, said second portion of said input shaft having anexternally splined section, said selective connecting means comprisingmeans for axially shifting said input shaft between a first positionwith said splined section engaging the internal splines of one of saidpinions and a second position with said splined section engaging theinternal splines of the other of said pinions.
 14. The drive of claim 13wherein said shifting means has an intermediate position with saidsplined section of said input shaft spaced between said internal splinesof said sun gears.
 15. The drive of claim 12 wherein said selectiveconnecting means comprises an axially movable sleeve surrounding andhaving a splined connection with said second portion of said input shaftand having opposite ends, said sun gears being rotatably mounted on saidsleeve between said ends thereof, said sun gears respectively havingclutch teeth on the sides thereof facing said ends of said sleeve, saidsleeve having clutch teeth respectively formed on said opposite endsthereof, and means for selectively axially shifting said sleeve betweena first position with the clutch teeth at one end thereof engaging theclutch teeth on one sun gear and with the clutch teeth at the other enddisengaged from the clutch teeth on the other sun gear, and a secondposition with the clutch teeth at the other end of said sleeve engagingthe clutch teeth on the other sun gear and the clutch teeth at said oneend disengaged from the clutch teeth on said one sun gear.
 16. The driveof claim 12 wherein said selective connecting means comprises first andsecond clutch means for respectively drivingly connecting said sun gearsto said second portion of said input shaft.
 17. The drive of claim 16wherein said sun gears are rotatably mounted on said second portion ofsaid input shaft, each of said clutch means comprising a driven clutchdisc secured to the respective sun gear and spaced therefrom, astationary clutch disc secured to said second portion of said inputshaft between said driven disc and the respective sun gear, a pressureclutch disc having a splined connection with said second portion of saidinput shaft, said driven disc being disposed from said stationary discand pressure disc, spring means for normally biasing said pressure andstationary discs away from engagement with said driven disc, and meansfor selectively moving said pressure disc toward said driven discthereby drivingly to clamp said driven disc between said stationary andpressure discs.
 18. The drive of claim 17 further comprising firstactuator means mounted in said spindle for actuating the pressure discof one of said clutch means, a cover member secured to said second hubportion of said housing, and second actuator means mounted in said coverfor actuating the pressure disc of the other of said clutch means. 19.The drive of claim 1 wherein said connecting means comprises a splinedsection on said input shaft and mating splines on said sun gear, saidinput shaft being axially movable between a drive position with saidsplined section engaging said sun gear splines, and a disconnectedposition with said splined section disengaged from said sun gearsplines.
 20. The drive of claim 19 further comprising spring means fornormally biasing said input shaft to said drive position thereof, acover member secured to said second hub portion, said cover memberhaving a hub portion coaxial with said input shaft and having a coaxialopening therethrough, a disconnect member in said opening and axiallymovable therein with said input shaft between said positions thereof,and a disconnect cap removably secured to said cover member and coveringsaid opening therein, said cap having a projection thereon, said capbeing adapted to be secured to said cover member in a first positionwith said projection disengaged from said disconnect member, said sprIngmeans biasing said input shaft and disconnect member to said driveposition in said first cap position, said cap being adapted to besecured to said cover member in a second position with said projectionengaging said disconnect member and moving the same and said shaft tosaid disconnected position in said second cap position.